The present invention is directed to processing materials and in particular micro or nanostructures and their applications. More particularly, the present invention provides methods and resulting structures for forming nano and micro structures using a deposition technique for a wide variety of applications. As merely an example, such deposition techniques can be applied to formation of one or more films in the manufacture of electronic devices, such as integrated circuits. But it would be recognized that the invention has a much broader range of applicability. The present invention may be used for etching, enhancing chemical reactions, and the like. Additionally, the invention can be applied to various fields including life sciences, chemistry, petrochemical, electronics, and others.
Over the years, microelectronics have proliferated into many aspects of modern day life. In the early days, Robert N. Noyce invented the integrated circuit, which is described in “Semiconductor Device-and-Lead Structure” under U.S. Pat. No. 2,981,877. Integrated circuits evolved from a handful of electronic elements into millions and even billions of components fabricated on a small slice of silicon material. Such integrated circuits have been incorporated into and control many conventional devices, such as automobiles, computers, medical equipment, and even children's toys.
Conventional integrated circuits provide performance and complexity far beyond what was originally imagined. In order to achieve improvements in complexity and circuit density (i.e., the number of devices capable of being packed onto a given chip area), the size of the smallest device feature, also known as the device “geometry”, has become smaller with each generation of integrated circuits. Increasing circuit density has not only improved the complexity and performance of integrated circuits but has also provided lower cost parts to the consumer.
An integrated circuit or chip fabrication facility can cost hundreds of millions, or even billions, of U.S. dollars. Each fabrication facility will have a certain throughput of wafers, and each wafer will have a certain number of integrated circuits on it. Therefore, by making the individual devices of an integrated circuit smaller, more devices may be fabricated on each wafer, thus increasing the output of the fabrication facility. Making devices smaller is very challenging, as each process used in integrated fabrication has a limit. That is to say, a given process typically only works down to a certain feature size, and then either the process or the device layout needs to be changed. Additionally, as devices require faster and faster designs, process limitations exist with certain conventional processes and materials.
An example of such a process is chemical vapor deposition, commonly called CVD. More particularly, CVD has been regarded as one of the most cost-effective means of high-throughput, high-quality thin film deposition for the manufacture of electronic, optoelectronic, and MEMS devices. In a conventional CVD reactor, for example, vaporized chemical precursors are in contact with a heated substrate, and deposition is the result of chemical reactions occurring on or very near the surface of the heated substrate. The composition of the deposit depends on the chemical precursors and the reactor's environment. For example, using a titanium precursor one could produce a metallic, titanium film on the substrate, or with a suitable partial pressure of oxygen in the reactor, a titania, TiO2 film could be formed. To form electronic circuits, CVD is often used with lithographic processes. For example, a film of material is deposited using CVD. Structures are etched from the film. The deposition and etch process can be repeated to form complex structures.
Other CVD techniques have also been proposed. An example of such CVD technique is Laser Assisted CVD. Unlike conventional CVD where the entire substrate is heated, Laser Assisted CVD (LCVD) uses a focused laser to locally heat a small spot on the substrate to suitable CVD reaction temperatures. Typical laser spot sizes are on the order of several microns. Because of the localized heating, the reaction pathway in the vapor is three dimensional, and the growth rates are several orders of magnitude higher than traditional CVD. LCVD growth rates of 5-20 microns/sec are often typical. The laser spots, however, often require a high power laser source, which is not efficient and costly. By translating the focus of the beam, it is possible to write lines, dots, and rods. Although CVD and LCVD have had certain success, many limitations still exist. That is, line widths associated with these processes often cannot be less than a predetermined amount, i.e., diffraction limit of light. Additionally, film quality often degrades as line widths become smaller. These and other limitations will be described in further detail throughout the present specification and more particularly below.
From the above, it is seen that an improved technique for processing materials is desired.